Lindsay Lane KC and William Duncan appeared for the second defendant (“Aspire”) in an appeal of the judgment of Meade J finding that a patent for the use of fluprostenol isopropyl ester (“FIE”), a prostaglandin F2α (“PGF2α”) analogue, also known as travoprost, for the treatment of glaucoma and ocular hypertension was valid and infringed. The appeal related to the Judge’s findings regarding obviousness over prior art known as Stjernschantz and an insufficiency squeeze.
The Court of Appeal dismissed the appeal. Arnold LJ found that, on the evidence, Meade J was entitled to conclude that the obvious way forward from Stjernschantz was to consider further prostaglandin analogues, but that it would not be obvious to try FIE. The insufficiency/implausibility attack had been argued as a squeeze in the event that the patent was found to be inventive by disclosing reduced irritation (ie at the priority date it had been understood that use of PGF2α isopropyl ester would cause irritation). Given the finding of inventiveness was not based on reduced irritation, this attack fell away.